The present invention relates to multipurpose folding tools, and in particular to a handle structure and pivotally interconnected blades or jaws for such tools.
Folding scissors of various types have been known for many years and have long been included in multipurpose folding tools. In the past, most folding scissors in such multipurpose tools have been very small, and therefore relatively ineffective.
One type of folding scissors in a multipurpose tool is disclosed, for example, in Moser U.S. Pat. No. 696,995. In that type of tool one blade of a pair of scissors has an extended handle which is attached to pivot the entire pair of scissors into a storage slot in a knife handle. A second handle and its attached scissors blade are also stowed in the same slot, with the scissors blades and handles generally parallel with one another. A small leaf spring is typically used to urge the handles apart from each other to open the blades of such a pair of miniature scissors, and the spring is kept compressed when the scissors are in the stowed position. The spring typically used in such scissors is easily lost or accidentally bent to an inoperative condition.
East German Patent Publication 2,322,229 discloses another type of folding scissors using a long spring in a handle of a tool to move an auxiliary lever to urge a handle of a movable scissors blade in a blade-opening direction. This arrangement, however, fails to hold the handle of the main scissors blade stably fixed relative to the tool handle when the movable scissors handle and blade are urged in a blade-closing direction with respect to the main blade.
German Patent No. 145784 discloses a tool incorporating a folding handle with a pair of scissors blades which can be stowed within a multipurpose tool handle, but such scissors include the previously mentioned type of spring or none at all.
In previously-known folding scissors including a spring for opening the scissors blades, the force needed to move the blades in a closing or cutting direction has increased with continued closing movement of the blades. It is therefore desired to provide scissors which are easier to use in that the force needed to close the blades completely is not greatly increased over that required to close the blades partially during a cutting stroke of the scissors.
Many types of multipurpose pocket tools and pocket knives are known in which various knife blades, screwdrivers or other tool bits fold into storage locations within either a handle, or pair of handles. In some such multipurpose pocket tools, the handles are configured as channels of formed sheet metal that are able to pivot around the bases of a central pair of tool blades or jaws to reduce the size of the channel shaped handles as the outer surface of the folded tool.
In the case of previously known multipurpose folding hand tools, the typical channel-shaped handles do not provide spring pressure separately to each blade in order to hold it in the closed or open position. There is typically one spring, usually integral to the handle, which cannot hold all the blades contained within closed without some looseness. Therefore, the typical way to hold the blades closed is by side friction applied by the blade pivot pin. Blade looseness may allow the tips of the blades to open slightly, exposing the sharp and potentially dangerous edges. Side friction can sometimes be overcome by a jolt to the tool, causing the blades to unfold partially, exposing the sharp and potentially dangerous edges. The ideal side friction required for holding the blades in the channel-shaped handles without individual springs requires manual adjustment and is difficult to achieve. Channel-shaped handles are thus difficult to manufacture and assemble. For these reasons, it has become customary for good tool design to dictate that handles of a pair first be spread apart from each other in order to gain access to the blades contained within the handles. When the tool is folded closed, the opposite tool handles prevent the accidental partial opening of the blades.
In some pocket knives, the handles are configured as generally flat pieces of sheet metal which sandwich the various blades. Each blade pivots about a pin located at its base and is held either open or closed by an individual spring which must be supported at its base and near its center in order to provide adequate spring pressure. This center support is typically provided by a pin.
Each blade of a pocket knife typically has its own individual spring to bias it closed. This allows the blades safely to be located on the outside of the tool, as they cannot accidentally open. If a jolt to the knife partially opens a blade, its spring forces it closed again. The typical generally flat handle pieces are what provide support to keep the three pins where they are required to make the individual springs work. The individual spring and three-pin design, however, represents less efficient use of space than the channel-shaped handle design typically used in multipurpose folding hand tools.
What is needed, then, is an improved multipurpose folding tool including a central folding tool easily used, and which does not interfere with the utility of other folding tool bits included in the multipurpose folding tool. It is also desired for such folding scissors to be larger than previously available folding scissors included in a multipurpose folding tool of a comparable size, and that the entire tool in a folded configuration can be easily carried in a person""s pocket without causing unnecessary wear of the fabric of the pocket. It is also desired for individual blades of a multipurpose tool to be held securely so that they can safely be located on the outer side of a handle of such tool in its folded configuration. Finally, it is desired for such a multipurpose tool to be simple to assemble and to be able to be assembled in different arrangements.
The present invention provides a multipurpose folding tool which overcomes the previously-mentioned shortcomings and disadvantages of previously known folding tools by providing improved folding scissors and other tools having pivotally interconnected jaws or the like.
In one embodiment of the present invention a channel-shaped folding handle is attached to each of a pair of interconnected movable members such as the blades of a pair of scissors and a pair of springs in each handle operate, respectively, on the attached member, such as a scissors blade, and on an adjacent rocker. Both of such springs in each handle operate to hold the handles together with the multipurpose tool in a folded configuration. With the scissors, for example, ready for use, one spring in each handle holds the attached scissors blade securely aligned with the handle, while the other spring operates the associated rocker to urge the scissors blades toward an open position after each cutting stroke. Each rocker is linked with the adjacent scissors blade so that the rocker is free to pivot through a small angle relative to the blade but is moved along with the blade between the stowed position and the deployed position of the blade.
In a preferred embodiment of the invention, additional folding tool bits are included in the handles, mounted on tool pivot shafts spaced apart in the handles from the location of the scissors blades. When such tool bits are used, the handles are prevented from moving laterally with respect to each other in one embodiment of the invention by an ear on one of the springs in each handle and by a portion of each rocker extending along-side the scissors blade associated with the other handle.
In one embodiment of the invention a lanyard-attachment ear mounted on a pivot shaft may be extended for use or folded into a stored position where it is not likely to wear the fabric of a pocket in which the tool is carried.
Another embodiment of the present invention also provides a means of simplifying the manufacture and assembly of multipurpose folding hand tools by eliminating the channel-shaped handle construction while maintaining the efficient use of space provided by the channel-shaped handle design. In this embodiment of the invention, the traditional channel-shaped handle is replaced by two L-shaped handle pieces each having a flange included in a piece which is a side of a handle. Blades may be mounted at either end of the handle on pins which join the sides of the handle to each other. Each blade has its own spring which is attached to the handle by a pin or shaft through its base portion at the opposite end of the handle. Each spring is supported near its center by the flange that forms the leg of the L-shaped handle piece.
In multipurpose folding hand tools, this aspect of the invention allows the incorporation of an individual spring for each of the blades or other tool bits contained within the handles. These springs bias the individual blades closed and allow them to be accessible from the outside of the tool when the handles are folded closed without sacrificing safety. This eliminates the time-consuming task of opening the tool handles in order to open or fold away a blade. Manufacture is simplified by use of L-shaped handle pieces because handle side parallelism and hole alignment are facilitated, polishing is simplified because of improved access to the inside, and heat treatment warpage is reduced because of reduced internal stresses and increased robustness of the part. Assembly is simplified by eliminating the channel structure because the components can be stacked up one piece at a time, including the handle pieces, and fastened together rather than the internal components having to be stacked up and inserted into the channel structure.
According to this aspect of the invention two L-shaped handle pieces, the second one generally being the mirror image of, and optionally rotated 180xc2x0 from the first, replace the usual flat side pieces. There are two holes in each handle piece which, when arranged as described, generally line up with each other in order to accept pins which will attach the two pieces together.
In various embodiments of this aspect of the invention, blades or other tool bits may be attached at only one end, or at each end, of the handle. The blades may all fold out of one side of the handle, or from both sides. Each blade has its own spring, supported near its center by the flange, the leg of the L-shaped handle piece. This leg of the xe2x80x9cLxe2x80x9d efficiently replaces the traditional third pin. The spring for each blade also serves as a spacer for that blade at the opposite end of the handle. The number of blades a handle may contain is thus limited only by the width of the flange and the thickness of the blades and springs.
Laterally adjacent blades or tool bits in a handle are engaged by tapered tips of adjacent springs each engaging only a particular one of the adjacent blades.
In other embodiments of the invention, pliers or other tools may include jaws or jawlike members pivotally interconnected with each other and arranged to be folded and stowed in tool handles in a manner similar to that in which the scissors blades operate and are interrelated with the tool handles.
In one such embodiment of the invention at least one and preferably each of a pair of opposite handle sides includes a flange extending over most of its length, and a leaf spring extends from the flange longitudinally of the handle to bear on a surface of the base of a foldable tool blade. A pair of such handles may each have a base of one of a pair of pliers jaws between the handle sides at one end of each handle, while knife blades or other tool bits are located at the end of the handle where the leaf spring is located.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.